This blog features my weekly column called "What's up in the sky". It is published every Saturday in the Ellensburg newspaper, Daily Record (http://www.kvnews.com/). While my postings will be most accurate for Central Washington, readers throughout the northern USA may find something of use.

Tuesday, July 26, 2011

The Ellensburg sky for the week of 7/30/11

Saturday: Tonight’s Moon is new. Don’t bother looking for it. The new moon is the phase where the Moon is directly between the Earth and the Sun. Hence the side of the Moon facing Earth is not receiving any sunlight and cannot be seen. Typically a new Moon announcement is ho hum. But not during a meteor shower. The Southern Delta Aquarid meteor shower is just coming down from peak numbers and should provide increased early morning meteors for the next three weeks. These meteors appear to come from a point in Aquarius near the star Delta Aquarii, also known as Skat. This point is about one and a half fists held upright and at arm’s length above the southeast horizon at 1 a.m. this week. You can follow this point throughout the night as it will remain a fist above Fomalhaut, the brightest star in that section of the sky.

Sunday: What are some of the signs of August? 1. Hot weather. 2. Back to school sales. 3. A chain email saying Mars will look as big as a full moon this month. The first two are true. The third one never was and never will be. In August of 2003, Mars was as close to Earth as it had been in all of written history. With the right telescope magnification, it could look as large as the moon without magnification. But, even then, Mars did not appear even as large as Jupiter always does. This year, Mars is about half its maximum apparent size. Mars is one and a half fists above the east-northeast horizon at 4 a.m.

Monday: In Scotland, August 1 was known as Lammas, the festival of the first wheat harvest of the year. You can remember this by looking at Spica, named after the Latin word for “ear of wheat”, one fist held upright and at arm’s length above the west-southwest horizon at 9:30 p.m. August 1 is known as a cross-quarter day, a day approximately half way between an equinox and a solstice.

Tuesday: Have you ever built a house? You probably had some material left over. If scientists studied that material, they could learn a lot about how your house was constructed, the origin of your house. In fact, studying the building scraps would probably teach them more about the origin of your house than if they studied your house in its current state. After all, your house has been repainted and remodeled. Asteroids are the leftover material from the origin of our Solar System. Scientists study them to learn more about how the Solar System was formed. The NASA probe called Dawn is orbiting Vesta, one of the largest asteroids in the main asteroid belt between Mars and Jupiter. For more information about Dawn, go to http://dawn.jpl.nasa.gov/.

Wednesday: Saturn is one fist above the west-southwest horizon at 10 p.m., just above the nearly setting Moon.

Thursday: We read a lot about how kids nowadays are heavier than they used to be. You don’t read that about stars… until now. Last summer, astronomers from the European Southern Observatory discovered the most massive stars in the universe using their Very Large Telescope (yes, that’s its real name). These two stars are about 300 times more massive than the Sun or twice as massive as the largest stars previously known. In addition to being very massive, they are several million times brighter than our Sun. Their brightness compared to the Sun is the same as the Sun’s brightness compared to the full moon. Neither of these stars is visible from Ellensburg. For more information, go to http://www.eso.org/public/news/eso1030/.

Friday: Jupiter is a half a fist above the east-northeast horizon at midnight.

The positional information in this column about stars and planets is typically accurate for the entire week.